The present invention relates to the field of solid-phase chemistry. More particularly, the present invention relates to a method and apparatus for eluting photocleavable-linker attached chemical library compounds.
Combinatorial chemistry libraries or single chemistries can be produced by a method known as solid-phase synthesis. That process involves linking a first chemical xe2x80x9cbase structurexe2x80x9d molecule to solid support media and subsequently adding, seriatim, chemical building blocks, or, alternatively, effecting chemical structural changes to the base structure, e.g., ring opening or closing. The base structure molecule participates in one or more reaction steps with the added chemical building blocks. Chemical compounds, referred to as library compounds, descended from the base structure molecule, are thereby generated. Extremely large, diverse chemistry libraries can be synthesized in this manner.
Each library compound, and its base structure molecule precursor, is typically attached to the solid support media, typically inorganic or polymer beads, via a cleavable linker that covalently links the compound to the support media. The synthesized library compound remains linked to the support media until such time as it is deliberately removed therefrom. A synthesized library compound can be separated from the support media by cleaving the linker. One class of linkers, referred to as photocleavable linkers, are cleaved by exposure to light, such as long-wave ultraviolet light (UV). The process by which a synthesized compound is cleaved from the photocleavable linker and removed from the environment of the solid support media is termed photoelution.
Currently, chemists use mercury spot lamps for photoelution. While such a spot lamp generates sufficient light output, it provides uniform illumination across a relatively small circular region or spot on the order of 5 centimeters or less in diameter. As such, they are suitable for illuminating only one sample at a time. As conventionally practiced, a spot lamp and sample are placed inside a hood. Due to the amount of bench-top area required, only one or two lamps are typically placed within a given hood, limiting the amount of samples that can be photoeluted. Moreover, the small size of the uniformly illuminated region disadvantageously increases the likelihood of sample-to-sample variation in the amount of received radiation.
As such, it would be desirable to have a method and apparatus for simultaneously photoeluting a multiplicity of samples and for providing a substantially uniform dosage of radiation thereto.
A method for photoelution, and an apparatus suitable for implementing the method, are disclosed. According to the present method, photocleavable linker-attached library compounds are photoeluted from solid support media by (i) exposing the solid support media for a portion of the photoelution time to light having a spectral energy distribution appropriate for cleaving the photocleavable linker from the solid support, and (ii) eluting the library compound from the solid support with a solvent under controlled temperature with or without UV exposure.
An apparatus suitable for carrying out the present photoelution method includes means for substantially evenly illuminating the sample, means for controlling illumination time and intensity, and means for controlling sample environment including temperature and, optionally, atmosphere. In some embodiments, means for substantially evenly illuminating the sample includes means for stirring or agitating the sample.